West Ham United could well be ruing their decision to allow promising defender Aji Alese to leave the club this summer, with the 21-year-old having made an impressive start to life in the second tier with Sunderland.

The imposing centre-back had risen up through the Hammers' youth ranks to enjoy a brief taste of life at senior level under David Moyes in recent years, making two appearances for the Premier League side in total.

One of those rare outings had come in the Europa League last season in the group stage clash with Dinamo Zagreb, with the 6 foot 4 centre-back earning praise from now-retired West Ham skipper Mark Noble for his "fantastic" defensive display.

The Islington-born starlet - who also enjoyed brief stints on loan at Accrington and Cambridge United during his time at the London Stadium - was unable to build upon that European performance, however, having struggled to force his way back into contention for the remainder of the campaign.

That lack of game time ultimately saw the youngster seal a move to the Black Cats in the recent window, joining the newly-promoted Championship outfit for a reported fee of around £500k.

That figure appears something of a bargain following an impressive string of displays for the former England U20 international at the Stadium of Light, having begun to showcase his quality after an initial slow start in his new surroundings.

The £450k-rated ace has been restricted to just two substitute appearances totalling only six minutes in the first eight league games of the season, although he has since played the full 90 minutes in each of the last three games, with the arrival of new boss Tony Mowbray seeing him take on a more prominent role.

While typically a centre-back, Alese has shown his ability to feature at left-back in recent weeks, notably bagging a fine goal against Watford in the 2-2 draw at Vicarage Road prior to the international break.

The highly-rated ace has followed that up with another standout performance in the goalless draw with Preston North End last time out, with his match rating of 8.1, as per SofaScore, by far the highest of any player on the day.

That was no doubt a deserved rating as the former Irons starlet completed two tackles and an impressive seven clearances on what was his home debut, including a stunning goalline clearance to brilliantly deny opposition midfielder, Benjamin Whiteman.

That remarkable piece of defending was notably lauded by journalist Josh Bunting, who stated that it was "actually scary how easy he made that look", having prevented what looked like a certain goal for the visitors.

If the recent evidence is anything to go by, Alese is only set to go from strength to strength as the season progresses, with Moyes and co potentially set to be left to regret their decision to let him depart, particularly for what was a relatively small fee.